Optical nanoprobing of integrated circuits

Patent metadata

Field	Value
Publication number	US-2016377675-A1
Application number	US-201615192976-A
Country	US
Kind code	A1
Filing date	Jun 24, 2016
Priority date	Jun 25, 2015
Publication date	Dec 29, 2016
Grant date	—

Abstract

Apparatus for electrical and optical nanoprobing at resolution beyond optical diffraction limit. Navigation microscope is configured for navigation to a region of interest. A probe spatial positioner supports a fork and an oscillating piezotube is attached to the free end of the fork and provides an output indicating of a distance to the sample. A single-mode optical fiber having a near-field transducer formed at an end thereof is attached to the oscillating piezotube such that the near-field transducer extends below the oscillating piezotube towards the sample. A photodetector is positioned to detect photons collected from the sample. The near-field transducer may be formed as a tapered section formed at the end of the single-mode optical fiber, a metallic coating formed at a tip of the tapered section, and an aperture formed in the metallic coating so as to expose the tip of the tapered section through the metallic coating.

First claim

1 . A prober integrating a near-field transducer, comprising:
a probe spatial positioner; a fork attached to the positioner; an oscillating piezotube attached to a free end of the fork; electrical leads attached to the oscillating piezotube; an optical fiber having a near-field transducer formed at an end thereof, the optical fiber being attached to the oscillating piezotube such that the near-field transducer extends below the oscillating piezotube; wherein the near-field transducer comprises a tapered section formed at the end of the optical fiber, a metallic coating formed at a tip of the tapered section, and an aperture formed in the metallic coating so as to expose the tip of the tapered section through the metallic coating.

2 . The prober of claim 1 , wherein the near-field transducer further comprises a metal tip extending from the metallic coating.

3 . The prober of claim 2 , wherein the metal tip extends to a height of from 50 nm to 100 nm and has a tip apex of diameter of from 20 nm to 30 nm.

4 . The prober of claim 2 , wherein the aperture has a C shape, and the metal tip is formed at central part of the c-shape aperture

5 . The prober of claim 1 , wherein the metallic coating comprises a gold layer.

6 . The prober of claim 1 , further comprising alignment marks provided on the metallic coating.

7 . The prober of claim 6 , wherein the alignment marks comprise metallic bumps.

8 . The prober of claim 6 , wherein the alignment marks comprise etched marks.

9 . The prober of claim 1 , wherein the tip of the tapered section has a diameter smaller than wavelength of photons to be detected.

10 . A method for fabricating a near-field transducer for operating at preselected wavelengths, comprising:
providing a single mode fiber having a diameter larger than the wavelengths; forming a thinned section at one end of the single mode fiber, wherein the thinned section terminates at a flat bottom having a diameter that is smaller than the wavelengths; coating the flat bottom with an opaque layer; cutting an aperture in the opaque layer, the aperture having dimensions optimized for the preselected wavelengths and being smaller than the preselected wavelengths; growing a metal tip on the opaque layer in the vicinity of the aperture; and, forming alignment marks on an outer perimeter of the opaque layer.

11 . The method of claim 10 , wherein the opaque layer is made of gold.

12 . The method of claim 10 , wherein the aperture is formed to have a C shape.

13 . The method of claim 12 , wherein the metal tip is formed at the center of the C shape aperture.

14 . The method of claim 10 , wherein the tip is grown to have a height of from 50 to 100 nm.

15 . The method of claim 10 , wherein the tip is grown using focus ion beam assisted chemical vapor deposition.

16 . The method of claim 10 , wherein the alignment marks are metallic bumps grown using focused ion beam.

17 . The method of claim 10 , wherein the alignment marks are etched onto the opaque layer using focused ion beam.

18 . An apparatus for performing electrical and optical sample nanoprobing with resolution beyond optical diffraction limit, comprising:
a sample holder; a navigation microscope configured for navigation over the sample to a region of interest (ROI); a probe spatial positioner; a fork attached to the positioner; an oscillating piezotube attached to a free end of the fork and providing an output indicating of a distance to the sample; electrical leads attached to the oscillating piezotube; a single-mode optical fiber having a near-field transducer formed at an end thereof, the optical fiber being attached to the oscillating piezotube such that the near-field transducer extends below the oscillating piezotube towards the sample; a photodetector; wherein the near-field transducer comprises a tapered section formed at the end of the single-mode optical fiber, a metallic coating formed at a tip of the tapered section, and an aperture formed in the metallic coating so as to expose the tip of the tapered section through the metallic coating.

19 . The apparatus of claim 18 , further comprising:
a laser positioned to provide a laser beam into the single-mode optical fiber; a collection objective positioned to collect light reflected from the sample and direct the reflected light onto the photodetector; a polarizer positioned between the collecting objective and the photodetector.

20 . The apparatus of claim 18 , further comprising:
a laser positioned to provide a laser beam towards the sample; an objective positioned to focus the laser beam from the laser source onto the ROI; a polarizer positioned at an exit side of the single-mode optical fiber; wherein the photodetector is positioned behind the polarizer and receives light passing through the polarizer.

21 . The apparatus of claim 18 , further comprising a plurality of conductive nanoprobes attached to the positioner and electrically coupled to a signal source.

22 . The apparatus of claim 21 , further comprising a polarizer positioned at an exit side of the single-mode optical fiber; and wherein the photodetector is positioned behind the polarizer and receives light passing through the polarizer.

23 . The apparatus of claim 21 , further comprising a laser positioned to provide a laser beam into the single-mode optical fiber.

24 . A method of probing a sample in a probing system using a near-field transducer (NFT) integrated with a nanoprober, comprising:
affixing a sample to a stage; affixing a single mode fiber optic, having an NFT formed at its sampling tip, to a piezo tube, wherein the piezo tube is attached to a fork of a nanoprober; using the stage to register a region of interest (ROI) of the sample to coordinates of the probing system; energizing a positioner of the nanoprober to bring NFT to within a prescribed distance from top surface of the ROI, wherein the prescribed comprises near-field proximity; determining proximity of the NFT to the top surface by monitoring of dampening of piezo tube; scanning the NFT over the top surface of the ROI.

25 . The method of claim 24 , wherein monitoring of dampening of piezo tube comprises monitoring amplitude, phase or amplitude and phase of oscillations of the piezo tube.

26 . The method of claim 24 , further comprising illuminating the ROI with a laser beam.

27 . The method of claim 26 , wherein illuminating the ROI with a laser beam comprises directing the laser beam into the single mode fiber optic.

28 . The method of claim 26 , wherein illuminating the ROI with a laser beam comprises directing the laser beam onto the ROI using a focusing optics.

29 . The method of claim 28 , further comprising using a photodetector to detect photons collected from the sample by the single mode fiber optic.

30 . The method of claim 29 , further comprising placing a polarizer between the photodetector and an exit end of the single mode fiber optic.

31 . The method of claim 24 , further comprising contacting the sample with a plurality of conductive nanoprobe tips and applying test signals to the sample via the nanoprobe tips.

32 . The method of claim 31 , further comprising using a photodetector to detect photons collected from the sample by

Assignees

• Fei Co

Inventors

• Ukraintsev Vladimir A
• Berkmyre Mike

Classifications

• B82Y35/00

  Methods or apparatus for measurement or analysis of nanostructures · CPC title

• G01N21/658

  enhancement Raman, e.g. surface plasmons · CPC title

• Y10S977/901

  having step or means utilizing electromagnetic property, e.g. optical, x-ray, electron beamm · CPC title

• G01R31/311 Primary

  of integrated circuits {(G01R31/31728 takes precedence)} · CPC title

• G01N29/2462

  Probes with waveguides, e.g. SAW devices · CPC title